Mid-infrared optical response to magnetic field in the La0.65Ba0.35MnO3 film grown by PLD

•Mid-infrared optical response to CMR is studied in the La0.69Ba0.31MnO3 film at room temperature.•High magnetotransmission and magnetoreflection of natural light reach up to 10% in the wide IR range.•The observed magneto-optical effects are described in framework of the theory of magnetorefractive effect.•High optical response of the La0.65Ba0.35MnO3 film to magnetic field could be used in the design of sensors. Optical and magneto-optical properties of the La0.65Ba0.35MnO3/SrTiO3(001) thin film with CMR and the paramagnetic-to-ferromagnetic transition at T = 310 K have been investigated in the infrared spectral range. It is shown that magnetotransmission and magnetoreflection of unpolarized light in the film reach up to 10 % at the magnetic field of 4kOe. The possible physical mechanisms responsible for negative magnetotransmission and positive magnetoreflection in the mid-infrared range are interpreted in the framework of the theory of magnetorefractive effect in manganites. High optical response of the La0.65Ba0.35MnO3 film to an external magnetic field (up to ∼ 25 %/kOe in the magnetoreflection) could be used in the design of optical magnetic field sensor, switches and modulators.